Lead-induced behavioral disorders in the rat: effects of amphetamine.

The effects of d-amphetamine on several measures of activity and spontaneous alternation were evaluated in rats chronically exposed to a low level of lead acetate via maternal milk during the neonatal period. Alterations in the amphetamine responses of lead-treated rats were observed with some measures of activity and exploration but not with others. 'Paradoxical' responses were observed with postural rearing and spontaneous alternation.

Marijuana: effects on free recall and subjective organization of pictures and words.

The free recall of pictures and words was compared following the administration of marijuana or placebo in a multitrial free recall task. Since pictures are thought to be registered in both visual and verbal memory stores with this encoding being mediated by some form of mental imagery, it was predicted that marijuana would produce a greater deficit in word recall in comparison to picture recall because the drug has been reported to facilitate imagery. A trend in the opposite direction followed intoxication; picture recall was inferior to word recall in the later stages of acquisition.

Marijuana and memory impairment: effect on free recall and recognition memory.

The effect of marijuana on memory was evaluated by presenting two groups of 17 male volunteers with lists of repeated or nonrepeated words following administration of a single marijuana cigarette containing 14 mg delta9-THC. An immediate free recall, final free recall and recognition memory test followed. Results indicated that marijuana significantly decreased immediate and final free recall but only slightly influenced recognition memory.

Marijuana: effects on storage and retrieval of prose material.

In a two phase design, an attempt was made to differentiate the effect of marijuana on the storage and retrieval of prose material. In the first phase, 40 male subjects were administered a single 500 mg marijuana cigarette containing 2.1%delta9-THC or a placebo cigarette.

Marijuana: dose-response effects on pulse rate, subjective estimates of potency, pleasantness, and recognition memory.

34 experienced marijuana users were divided into four equated groups of eight subjects each based on recognition memory test performance. One week later each group was retested following administration of marijuana containing 0, 5, 10 or 15 mg delta9-tetrahydrocannabinol. A dose-related effect of marijuana on pulse rate and subjective measures of potency and pleasantness occurred.

Marijuana and memory impairment: the effect of retrieval cues on free recall.

In an attempt to ascertain the effect of retrieval cues on recall deficits which occur following intoxication with marijuana, 40 male volunteers were presented with word lists following the smoking of a single one gram marijuana (0.94% delta 9 -THC) or placebo cigarette and then were required to recall these words immediately after presentation. Recall occurred under a condition in which cues representative of to-be-remembered words were present or in an uncued condition.

Lead-inducing hyperactivity. Chronic exposure during the neonatal period in the rat.

The effects of chronic exposure to low levels of lead via maternal milk during the neonatal period in the rat were evaluated by means of several activity measures, spontaneous alternation in the Y-maze, and weight data. Animals reared at the highest concentrations of lead showed retarded body growth. Lead-treated rats were found to be more active in the Y-maze and in the tilt-box, but not in the running wheel.

The behavioural final common path.

In this paper it is argued that any model of the motivational (i.e. reversible) processes governing the behaviour of an animal can be represented by means of isoclines in a multidimensional 'causal-factor space'.

Proteinase Inhibitor-inducing Factor in Plant Leaves: A Phylogenetic Survey.

Thirty-nine plant species representing 20 families from the four major divisions of plants were surveyed for the presence of proteinase inhibitor-inducing factor activity in leaves or other tissues. Tissue juices were assayed for their capacity to induce accumulation of proteinase inhibitor I in excised tomato (Lycopersico esculentum) leaves. In tissues of only 2 of the 39 species was proteinase inhibitor-inducing factor-like activity not found.